The present invention relates to an improved cutter, and more particularly to a cutter which has an improved depth gauge.
Cutters for endless cutter devices movable along a path for cutting a kerf in a work piece, such as may be found in a saw chain for cutting wood, generally have a cutter portion with a leading cutting edge and a depth gauge portion spaced forwardly of the cutting edge to control the depth of cut taken by the cutter. The depth gauge is instrumental in reducing the possibility of kickback during operation of the saw on which the chain runs.
Depth gauges in the past generally have included a single thickness of cutter material which extends upwardly in a region spaced forwardly from the cutter edge as disclosed in Silvon U.S. Pat. No. 4,353,277. Others have included bent-over depth gauge portions such as disclosed in U.S. Pat. Nos. 5,085,113 and 4,989,489 to Pinney, U.S. Pat. No. 4,911,050 to Nitschmann and U.S. Pat. No. 4,841,825 to Martin.
The single thickness upright depth gauge as illustrated in U.S. Pat. No. 4,353,277 may have a tendency to dig into the work piece and not provide consistent cutting depth control. Further it is less stable than a bent-over depth gauge. The bent-over depth gauges illustrated in U.S. Pat. Nos. 4,911,050; 4,989,489; and 5,085,113 generally have substantially rectangular configurations as viewed in plan. The depth gauge of U.S. Pat. No. 4,841,825 wraps over the majority of the chain width and substantially encloses the space leading the cutter edge. Although these prior devices produce depth of cut control, they can produce excessive friction and drag and also inhibit the free flow of chips produced by the cutters. Explaining further, if chips produced by the cutter are not allowed to flow easily under the top plate of the cutter they will continue to build up in the kerf, and the depth gauge and cutter will tend to ride thereover producing inefficient cutting.
An object of the present invention is to provide a cutter having a novel depth gauge leading a cutter edge which overcomes the disadvantages of prior devices.
More specifically, an object of the present invention is to provide a cutter having a bent-over depth gauge leading a cutting edge, which depth gauge has a rear edge with a central portion nearest the cutting edge of the cutter and at least one side portion which extends forwardly and downwardly from the central portion at an angle relative to the center line of the cutter. This provides good stability, depth of cut control, and kickback control while permitting free flow of chips to clear the kerf cut in the work piece.
Another object is to provide such a novel cutter with a bent-over depth gauge in which the rear edge has a central portion nearest the cutting edge and side portions which extend forwardly and downwardly from the central portion, diverging from each other as they progress forwardly.
More specifically an object of the present invention is to provide such a novel cutter having a depth gauge with a narrow central portion at its rear edge which is at the greatest elevation for the depth gauge, with remainder portions of the depth gauge sloping downwardly therefrom on progressing forwardly in the cutter.
Still another object of the present invention is to provide a cutter with a novel bent-over depth gauge which has a minimum width at its greatest elevation, and on progressing forwardly and downwardly from such minimum width portion has a central region of maximum depth gauge width intermediate its rear and front edges, thus to provide good depth gauge control, cutter stability, free chip flow, and reduction of friction and drag on the cutter as it moves through the kerf in the work piece.
Yet another object is to provide a novel cutter for use in an articulated cutter chain having a clipped heel on the underside of the cutter and a bent-over depth gauge which will cooperate to assist in stabilizing the chain and minimize vibration during use of the chain.
In prior cutting devices, as with the present device, as the cutting portion is sharpened, such usually occurs from the front of the cutter which increases the size of the gullet space between the cutter edge and the depth gauge. In past cutters, it has been found that increasing the distance between the depth gauge and the cutting edge often has increased kickback potential of the cutters. It has been found that the present invention and configuration of the depth gauge therefor maintains a greater degree of kickback control as sharpening occurs, thus resisting the tendency of prior devices to increase kickback through cutter life.
Yet another object of the present invention is to provide a cutter having such a novel depth gauge which has a maximum width that is at least as great or greater than the width of the cutter top plate and cutting edge to lend additional stability to the cutter during operation.